Study design The study will be a double-blind, randomized, placebo-controlled intervention trial. Children will be randomly assigned to one of two groups: antioxidant (AO) or placebo (P) supplement. If it is necessary to enroll children from different weight-loss programs, then randomization will be stratified by program. During the 4-month weight loss period, the AO group will consume oral supplements of ascorbic acid (500mg), alpha tocopherol (400 IU), and 50 µg selenium (all from Burgerstein Vitamins, Rapperswil-Jona, Switzerland) each evening with diner, whereas the P group will consume identical-appearing placebo supplements.